Before getting too excited about saving the earth...
http://www.dailymail.co.uk/health/article-1250532/Being-vegetarian-does-harm-environment-eating-meat.html
And the health benefits...
http://www.independent.co.uk/life-style/health-and-families/healthy-living/how-our-vegan-diet-made-us-ill-848322.html
I've seen acquaintances start out with veganism and look pretty good, as their bodies recovered from years of eating processed crap -- and then continue on to looking like they'd been in a concentration camp.